Causes of mortality of containerized western larch seedlings at the Champion Timberlands Nursery, Plains, Montana, were investigated. Seedlings were rated for disease severity based on extent of foliar decline symptoms and fungal isolations made from their roots. Isolations were also made from selected larch seed. Consistent associations between root colonization...
Mortality of western white pine transplants used to assess resistance to blister rust at the USDA Forest Service Nursery in Coeur d'Alene, Idaho was likely due to extensive root infection by Pythiva app. Severity of foliar symptom production was significantly correlated with extent of root system colonization by these fungi....
Eighteen isolates of Fusarium comprising four species (F. oxysporum, E. avenaceum, E. acuminatum, and F. sambucinum) isolated from diseased conifer seedlings from nurseries were tested for pathogenicity on Douglas-fir germlings. Three of the most pathogenic F. oxysporum isolates on Douglas-fir germlings were also tested on ponderosa pine germlings and older...
Investigations were conducted to determine importance of Fusarium as a pathogen on Douglas-fir seed and containerized seedlings at the Plum Creek Nursery during 1985. Fusarium oxvsnorum was occasionally isolated from necrotic lesions on young germinants that lacked foliar symptoms. Low levels of F. oxvsnorum were detected on three of four...
Containerized western larch, Douglas-fir, grand fir, subalpine fir, and ponderosa pine seedlings which displayed disease symptoms were sampled for presence of Fusarium spp. Seedlings from 33 seedlots within the Northern Region were sampled. Major types of diseases included post-emergence damping-off, root disease (late damping-off), and cotyledon blight. Fusarium oxysporum was...
Isolates of Botrytis cinerea from containerized conifer seedlings from two
nurseries in the Northern Rocky Mountains were exposed to the
dicarboximide fungicides vinclozolin and iprodione and the chlorinated
nitroaniline fungicide dicloran to evaluate occurrence and characteristics
of resistant strains. The isolates were grown on test media prepared by
incorporating the...
Isolates of Fusarium oxysporum, F. acuminatum, and F. sambucinum obtained from peat-vermiculite soil mixes were tested for pathogenicity on ponderosa pine, lodgepole pine, western larch, and blue spruce containerized seedlings and on germination of Scots pine and blue spruce seed. Ponderosa pine seedling were the least susceptible to killing by...
Root disease of 2-0 western white pine seedlings occurred at the Coeur d'Alene Nursery in 1982 within seedbeds fumigated with methyl bromide and chloropicrin. Although losses were not substantial, there were several groups of dead seedlings within affected seedbeds. Fusarium oxysporum was most often isolated from diseased roots. Other Fusarium...
A survey for incidence and distribution of root diseases was conducted on the Kootenai National Forest using timber inventory subcompartments as primary sample units. Root diseases were located within 23 of 75 sampled subcompartments. At least 1.1 percent of the commercial forest lands within the Forest are infested with root...